This invention relates to self-priming systems for liquid pumps and more particularly to a self-priming pump system wherein a fast-acting, tee-type priming valve is provided to permit automatic priming of the pump.
Self-priming liquid pumping systems are disclosed in U.S. Pat. Nos. 3,370,604 and 3,381,618, each of which is commonly owned by the assignee of the present invention. As there shown, a pump is positioned so that its suction inlet line is submerged in a suction chamber, and a check valve is provided in the discharge to prevent reverse flow of liquid when suction is lost. A priming valve is positioned between the pump discharge and the check valve to permit the column of liquid therebetween to flow back to the suction chamber and prime the pump.
Previous priming valves included spring-biased valves responsive to liquid dynamic pressure to control the flow of priming liquid to the pump suction inlet. Actuation of the priming valve was by means of a pressure sensing tube which extended into the flow stream, or, alternatively, a venturi was provided to sense the reduced static pressure of the flowing fluid as it passed through the throat of the venturi, and each arrangement caused the priming valve to open when no flow was taking place.
Although the prior art priming valves are entirely suitable for their intended purpose, it is desirable to provide a more rapid acting priming valve construction.